This invention relates generally to the field of modular electronic systems, and more particularly to a method and system for monitoring the thermal status of a card shelf.
Modular electronic systems are generally configured as a shelf to optimize space efficiency within a central office or other similar facility. Card shelves include individual plug-in electronic module cards having different functions that communicate across a backplane. The electronic cards have different thicknesses depending on the amount of electronic circuitry contained in each electronic card. The electronic cards may also have flanges at the top or bottom which fit into grooves in the card shelf for sliding the electronic cards into the card shelf and plugging the electronic cards into connectors located in the backplane of the card shelf.
The card shelf may also include an open or perforated top and bottom portion to allow thermal energy generated by the electronic cards during operation to escape the card shelf. Additionally, the card shelf may include a fan assembly for directing air flow through the card shelf to dissipate the thermal energy generated by the electronic cards during operation. The fan assemblies include air filters to purify air and remove harmful dust and other contaminants.
Known card shelves present certain drawbacks. For example, to maximize space within a card shelf, electronic cards are placed in close proximity to one another. As a result, dissipation of thermal energy generated by the electronic cards during operation must be closely monitored in order to maintain proper operation of the electronic cards.
Typical fan assemblies and other active cooling systems use a flow sensor to monitor the performance of air filters which can become clogged and reduce the dissipation of thermal energy in the card shelf. Such flow sensors, however, are expensive and inaccurate, frequently generating false alarms that cause excess maintenance, servicing, and down time. In addition, conventional systems are unable to provide diagnosis of problems within the cooling system.
The present invention provides an improved method and system for monitoring the thermal status of a card shelf. In particular, an array of operating temperatures of cards within the card shelf are collected along with an ambient temperature. The temperatures are together used to generate a thermal map of the card shelf and to diagnose failure conditions within the cooling system for the card shelf.
In accordance with one embodiment of the present invention, a method for monitoring the operating temperature within a card shelf having a plurality of discrete electronic cards includes receiving a first temperature indicative of an operating temperature of an item on one of the electronic cards. A second temperature indicative of an ambient temperature in which the electronic card is operating is also received. Based on the first and second temperatures, the temperature controller determines whether the item is operating below a specified limit.
In accordance with another aspect of the present invention, a method for monitoring a fan assembly having at least one fan for each of a plurality of temperature zones in a card shelf includes receiving a plurality of temperature inputs for each temperature zone in the card shelf. The temperature inputs each are indicative of an operating temperature of an item within the temperature zone. A temperature profile for each zone in the card shelf is determined based on the temperature inputs for the zone. In response to at least one temperature profile for a zone being above a specified limit for the zone and a fan failure within the fan assembly, an alarm is generated indicative of a fan failure for the zone.
Technical advantages of the present invention include providing an improved temperature controller for a card shelf. In particular, temperature maps and profiles are generated on a per cooling zone basis. This allows the temperature controller to diagnose cooling failures and other conditions on a zone-by-zone basis and to alert the operator to real failure conditions. In addition, ambient temperature is sensed and used to determine the thermal status of items within the card shelf. As a result, variations in ambient temperature will not cause false alarms and true error conditions can be identified despite unfavorable environmental conditions.
Other technical advantages of the present invention will be readily apparent to one skilled in the art from the following figures, description, and claims.